Texas Instruments SN74AHCT540DGVR

Overview

SN74AHCT540DGVR from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for bus line driving and memory address register buffering in 5-V digital systems. It features TTL-compatible inputs, ±8 mA output drive, 5.5 V absolute max supply rating, and operates from –40°C to 125°C. Its dual 3-state enable (OE1/OE2) supports independent control of two 4-bit groups.

For engineers reviewing the SN74AHCT540DGVR datasheet, SN74AHCT540DGVR pinout, SN74AHCT540DGVR application, or SN74AHCT540DGVR equivalent, key selection criteria include 3-state timing (tPZH ≤ 9 ns), thermal resistance (RθJA = 92°C/W), input compatibility with legacy TTL logic, and TVSOP-20 package footprint constraints for high-density PCB layouts.

Technical Context

The SN74AHCT540DGVR implements dual 4-bit noninverting buffers with active-low 3-state enables (OE1, OE2), where either enable high forces all eight outputs into high-impedance. Its internal logic uses standard CMOS process with TTL-level input thresholds (VIL = 0.8 V, VIH = 2 V), ensuring interoperability with 5-V TTL families without level shifting.

Propagation delay is specified at CL = 15 pF (tPLH/tPHL ≤ 6 ns) and CL = 50 pF (≤ 10 ns), supporting reliable operation in address/data bus applications up to ~100 MHz. Output drive capability (±8 mA) meets LSTTL load requirements while maintaining VOH ≥ 3.8 V and VOL ≤ 0.44 V under full load.

Key Specifications

Pinout & Package

SN74AHCT540DGVR is housed in a 20-pin TVSOP (Thin Very Small Outline Package) with 0.5 mm pitch, body size 5.00 mm × 4.40 mm, and overall footprint 5.00 mm × 6.4 mm. The package places inputs (A1–A8, OE1, OE2) on one side and outputs (Y1–Y8) on the opposite side to simplify PCB routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal buffer applications.

Compared with SN74AHCT244DBR and SN74LVC244APWR, the SN74AHCT540DGVR uniquely delivers 5-V TTL compatibility, TVSOP-20 compactness, and dual independent 3-state control-making it optimal for space-constrained industrial upgrades and mixed-voltage bus isolation.

Availability

SN74AHCT540DGVR is available at Aetrix Electronics and suitable for industrial control systems, legacy system upgrades, and microcontroller-based data acquisition requiring stable component supply over extended product lifecycles.

Supply support for SN74AHCT540DGVR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74AHCT540DGVR belongs to TI's 74AHCT logic family, engineered for seamless 5-V TTL-to-CMOS interfacing in industrial and legacy-system applications where reliability, compatibility, and thermal performance are critical.

FAQ

What is the maximum operating voltage for SN74AHCT540DGVR?

The SN74AHCT540DGVR has an absolute maximum supply voltage of 7 V, but its recommended operating range is strictly 4.5 V to 5.5 V. Operation outside this range may cause parametric degradation or latch-up. The device is not rated for sustained 6-V operation, and VCC must remain within 4.5–5.5 V for guaranteed timing, drive strength, and logic threshold compliance per the SCLS268N datasheet.

Does SN74AHCT540DGVR support hot insertion?

No, SN74AHCT540DGVR does not support hot insertion. Its absolute maximum ratings specify that inputs (VI) and outputs (VO) must stay within –0.5 V to VCC + 0.5 V. During hot plug, floating VCC or uncontrolled voltage ramp-up can violate these limits, risking damage to internal protection diodes. TI recommends powering the SN74AHCT540DGVR before applying signals and using series resistors or dedicated hot-swap controllers if live insertion is required.

Can SN74AHCT540DGVR drive a 50-pF load with guaranteed timing?

Yes, SN74AHCT540DGVR guarantees switching characteristics up to CL = 50 pF: tPLH/tPHL ≤ 10 ns and tPZH/tPHZ ≤ 12 ns at VCC = 5 V and TA = –40°C to +125°C. These values are production-tested per the datasheet's Table 4.6, making it suitable for driving moderately loaded buses, such as those with multiple CMOS inputs or longer PCB traces, without timing violations in industrial temperature ranges.

Is SN74AHCT540DGVR pin-compatible with SN74LS244?

Yes, SN74AHCT540DGVR shares identical pinout and functional mapping with SN74LS244 (20-pin DIP/SSOP/TVSOP), including A1–A8, Y1–Y8, OE1, OE2, GND, and VCC positions. However, SN74AHCT540DGVR uses CMOS output stages and TTL-compatible inputs, offering lower ICC (4 µA vs. ~20 mA), wider VCC range (4.5–5.5 V), and improved noise immunity-enabling direct replacement without PCB changes.

What is the thermal resistance (RθJA) of SN74AHCT540DGVR in its TVSOP package?

The SN74AHCT540DGVR in the DGV (TVSOP-20) package has a junction-to-ambient thermal resistance (RθJA) of 92°C/W, as specified in Section 4.4 of the SCLS268N datasheet. This value assumes standard JEDEC 2-layer board conditions (1-inch² copper pad). For thermally demanding applications, designers should verify board layout against TI's recommended copper flood and via placement to maintain safe junction temperatures below 125°C under worst-case load.